.input{
    border: 6px solid aquamarine;
}
/* class重复 用className */

.show{
    /* opacity: 1;
    transition: all 1.5s ease-in forwards; */
    animation: show-item 2s ease-in forwards;
}
.hide {
    /* opacity: 0;
    transition: all 1.5s ease-in; */
    animation: hide-item 2s ease-in forwards;
}

/* 关键帧 */
@keyframes show-item{
    0%{
        opacity: 0;
        color:red;
    }
    50%{
        opacity: 0.5;
        color: blue;
    }
    100%{
        opacity: 1;
        color: green;
    }
}
@keyframes hide-item{
    0%{
        opacity: 1;
        color: red;
    }
    50%{
        opacity: 0.5;
        color: blue;
    }
    100%{
        opacity: 0;
        color: green;
    }
}